This invention relates to a tubing hanger for a subsea wellhead installed on the ocean floor. A need has long existed for an adjustable tubing hanger, adjustable between 6 and 10 feet, to set tension on the tie back. This invention relates to a tubing hanger, which is adjustable, so that the end of the tubing hanger does not need to be cut during the installation process to fit the needed dimensions of the wellhead. The resulting system is a tension latching system which can be used on an offshore platform, such as a Spar, or a deep draft cassion vessel, a tension leg platform, (TLP), a compliant tower production rig or a jack up production rig.
During the completion of an offshore well, the tubing hangers are typically lowered into supported positions within the wellhead housing through a blowout preventer (BOP) stack installed above the housing. Often the fit is not exact, and the bottom portions of the tubing hangers need to be cut in order to provide a proper fit in the annulus of the wellhead housing.
An object of this invention is to provide an adjustable tubing hanger to eliminate of the tubing hanger components, to minimize the possibility of leakage due to inaccurate cuttings and uneven sealing surfaces.
An object of the invention is to provide a safer, and faster means of installing tubing hangers with significant environmental advantages, and lower construction costs.
The invention is for a wellhead using a tension latching system and a tension latching system, and a method for using a tension latching system. The tension latching system comprises a hanger, such as a casing hanger or a tubing hanger, having an inner barrel and a housing assembly for an inner barrel, and comprises a latching segment contained within the inner barrel, wherein the latching segment further comprises a profile with a first side for engaging the inner barrel with latching teeth and a second side abutting the housing of the inner barrel; an adjustable inner barrel connecting to the latching segment, having an inner surface and an outer surface, and further comprising inner barrel teeth disposed on the outer surface and the latching teeth engaging the inner barrel teeth in an interlocking engagement; at least one spring for energizing the latching segment against the adjustable inner barrel; a locking mechanism comprising a pin and a spring to orient the latching segment in the housing assembly of the inner barrel; a running tool having a tension adjusting feature which enables the inner barrel to be adjusted to tolerances within xc2xd inch which further consists of a pack off assembly with pack off seals adapted to ratchet the latching segment until the correct tension is achieved on the adjustable inner barrel.
The invention also relates to a method for latching a casing hanger for a subsea wellhead having an inner barrel and a housing assembly for an inner barrel, comprising the steps of: assembling a running tool with a pack off assembly on the running tool, wherein the pack off assembly has a split ring latching mechanism and a locking mechanism comprising a pin and a spring; stabbing into the inner barrel engaging the split ring latching mechanism, locking the pack off assembly to the inner barrel; pulling up on the running tool, forming tension on the running tool; adjusting the tension on the inner barrel to a predetermined amount of tension by ratching the latching segments against the inner barrel until the latching segment fixedly engages and locks the inner barrel in place; and removing the running tool from the pack off assembly.